Wasting Effects of the Ocean.

In the Memoirs of the Wernerian Natural History Society, Vol. III. p. 814., and in the Edinburgh Philosophical Journal, Vol. III. p. 42., the subject of the Wasting Effects of the Sea upon the firm ground, is variously treated by the writer; and is here alluded to, in reference to the production of the appearance termed a Ground-swell, so often observed on our shores. In these papers it has been assumed, that the German Ocean, or North Sea, bounded partly by the coasts of Great Britain, Norway, Denmark, Germany, Holland, and France, as will be seen from [Plate III.], is almost every where wasting and extending its margin, upon the principle of its forming the great receptacle for all the debris of the surrounding countries above mentioned, which have a direct tendency to lessen its capacity for containing the waters which flow into it from the Atlantic, by the apertures between the shores of Scotland and Norway, towards the north, and between Dover and Calais, to the south. These passages may respectively be conceived as admitting a constant quantity, while this great basin is continually receiving the debris of the extensive tracts of country which surround it, through the medium of the innumerable rivers and streams that fall into it.

Wasting Effects of the Ocean.

Upon similar principles, the extensive lakes of interior countries become so many receptacles for the debris of their respective districts; and must in the lapse of time, contain less water, in proportion to the cubical contents of solid matters carried into them. So it is upon the great scale with the basin of the North Sea, from the extensive banks deposited therein, which lessen its capacity, and thereby give a tendency to the water which flows into it to overflow and waste its margin, producing, under various modifications, those heavy swells in the Sea to which we now allude. With this state of things in view, we may now inquire into the effects of the storms which agitate the waters of the Atlantic, and reach our shores only in the form of what has been significantly termed a Ground-swell; which may partly be illustrated from the storm described in page [312]. of this work. We accordingly find the waters of the North Sea often in an agitated state, without any apparent cause, though no doubt proceeding from distant storms at sea. Hence, a continued gale from the westward, passing along the Atlantic Ocean, overcharges all the seas and inlets communicating immediately with it. Under these circumstances, although the surface of the North Sea be comparatively smooth, yet having acquired motion to a considerable depth from the distant storm, it continues to produce the effect of a Ground-swell for a considerable period. A swell of this description is almost constantly observable in the Bay of Biscay, owing to its exposure to the Atlantic, and from the configuration of the bounding land between Cape Finesterre in Spain, Ushant in France, and the relative position of the British Isles. Here the Ground-swells, proceeding from the same cause as those of the North Sea, are either the precursors of a gale of wind, or the effects of one which does not reach us.

Similar, though less evident effects, are produced by gales of wind which may be conceived to be confined to the boundary of the North Sea itself. Hence the heavy waves which often break upon the eastern shores of Great Britain, without any apparent cause at the time, are afterwards found to arise from storms at sea. But the heaviest Ground-swells of the North Sea are produced by gales from the north-east, which proceed in a progressive manner along the inclined plane of its bed, until the waves, by impinging upon the bottom and sides of the firm ground, are so disturbed that they ultimately cease, after wasting the whole extent of the shores, and sometimes causing the most destructive effects upon the coast of Holland, forming the southern extremity of this great basin.

No. VI.

Materials.

SCHEDULE, containing an Enumeration of the MATERIALS used in the Erection of the Bell Rock Light-House.

Course.Granite in Pieces.Sandstone in Pieces.Granite in cubic feet.Sandstone in cubic feet.Tons of Sandstone and Granite.Sandstone Joggles.Oak Trenails.Oak Wedges in pairs.Pozzolano in Barrels.Lime in Barrels.Sand in Barrels.
1 4 14 6 146 10.891 1.5 2.2 1.1
2 52 71 508 876 101.648 13 246 378 13.6 19.9 10.7
3 52 84 808 1269 152.797 13 246 437 16.9 24.8 13.3
4 52 71 696 1009 125.609 13 246 400 14.5 21.2 11.4
5 53 54 593 849 106.258 13 212 336 12.5 18.3 9.8
6 26 71 492 790 94.275 13 194 270 11.8 17.2 9.2
7 26 58 238 767 73.094 13 168 242 8.3 12.3 6.6
8 26 45 196 547 54.148 13 142 268 7.4 11.0 5.8
9 26 45 264 426 50.737 13 142 229 6.3 9.3 5.0
10 26 45 292 606 65.748 13 142 229 7.6 11.0 5.9
11 26 45 339 363 52.006 13 142 229 6.3 9.3 5.0
12 16 37 160 462 45.308 8 108 184 5.7 8.4 4.5
13 16 37 194 347 39.709 8 108 184 5.0 7.4 3.9
14 16 37 168 329 36.423 8 108 184 4.8 7.0 3.7
15 16 37 188 301 35.962 8 108 184 4.6 6.8 3.6
16 16 37 153 321 34.698 8 108 184 4.7 6.9 3.7
17 16 37 182 308 36.000 8 103 184 4.7 6.9 3.7
18 16 37 153 297 32.983 8 108 184 4.4 6.4 3.4
19 16 37 180 304 35.560 8 108 184 4.5 6.6 3.5
20 16 29 196 308 37.077 8 108 152 4.3 6.3 3.4
21 16 29 211 264 35.088 8 92 152 4.2 6.1 3.2
22 16 29 100 311 29.906 8 92 152 3.9 5.7 3.0
23 16 29 177 238 30.615 8 92 152 3.9 5.7 3.0
24 16 29 147 303 32.951 8 92 152 3.9 5.6 3.0
25 16 29 149 235 28.248 8 92 152 3.5 5.2 2.8
26 6 39 142 250 28.780 8 92 152 3.5 5.2 2.8
27 38 315 22.500 8 79 67 3.0 4.4 2.4
28 33 259 18.500 8 66 58 2.8 4.1 2.2
29 26 236 16.857 8 54 61 2.9 4.2 2.2
30 26 249 17.786 8 52 54 2.4 3.4 1.8
31 25 238 17.000 8 50 68 2.2 3.3 1.8
32 26 274 19.571 8 52 69 2.3 3.3 1.8
33 28 302 21.571 8 56 78 2.6 3.8 2.0
34 30 296 21.143 8 60 80 2.7 4.0 2.1
35 32 271 19.357 8 64 80 3.0 4.5 2.4
36 32 266 19.000 8 64 80 2.5 3.7 2.0
37 32 279 19.929 8 64 80 2.3 3.5 1.8
38 24 275 19.643 1.5 2.2 2.0
39 16 138 9.857 1.2 1.8 1.6
40 16 136 9.714 1.2 1.7 1.5
41 14 133 9.500 1.1 1.6 1.4
42 14 142 10.143 1.1 1.6 1.4
Over,59915246932160351678.59033840656329207.1303.8 165.4